UK standard 3 pin charging

[mukund]

[moved to UK and Ireland group]
Hi all,

I recently converted my garage and had one of these installed outdoors: Socket 13A
I am exploring a dedicated EV charger installation (as I am on EV tariff and will save a lot more with faster charging) but, waiting for quotes etc.
My M3SR was due in Feb 2022 but, now its coming in mid December.
If I am charging overnight via the standard outdoor 3 pin plug how safely can I sleep at night?
Overnight only the car will be charging via that socket/RCD.

Thank you in advance for replies.

 

[Adopado]

[moved to UK and Ireland group]
Hi all,

I recently converted my garage and had one of these installed outdoors: Socket 13A
I am exploring a dedicated EV charger installation (as I am on EV tariff and will save a lot more with faster charging) but, waiting for quotes etc.
My M3SR was due in Feb 2022 but, now its coming in mid December.
If I am charging overnight via the standard outdoor 3 pin plug how safely can I sleep at night?
Overnight only the car will be charging via that socket/RCD.

Thank you in advance for replies.

If it was recently installed by a competent electrician then it should be as good an option as any for use with the UMC. The thick cable on the UMC 13 amp plug may make it a challenge to fully close the cover but is advised in case of rain.

 

[Fursty Ferret]

If I am charging overnight via the standard outdoor 3 pin plug how safely can I sleep at night?

Very safely provided that the outdoor socket was installed by a competent person.

You could replace the double socket with a 16A commando, which would give you a 60% boost on charging speeds vs the normal socket and be a bit more weatherproof.

 

[MrBadger]

If it was recently installed by a competent electrician then it should be as good an option as any for use with the UMC. The thick cable on the UMC 13 amp plug may make it a challenge to fully close the cover but is advised in case of rain.

Fully competent person and registered against building control if you are in England as it is outdoors work so subject to part P.

The electrician should technically been told that it is for outside car charging so they would need to stuck to stricter regs but that is a tough one to prove if anyone came asking about it - more of a thing that may happen after an issue. This is more important if fitting a commando socket though.

As for closing cover, to add to the above, you may well have problems as it is a switched plug which will likely cause the sockets to be off centre. If that is the case and the centres to not line up exactly with the weatherproof openings, the thick cable on the UMC may make it very hard/impossible to kink the cable to line up correctly. An easy one to visually check if its likely to be an issue prior to needing it.

Another gotcha is how the socket is protected, particularly if it shares an RCD with other circuits in the house. Its not unheard of tripping a shared RCD due to exceeding the 30mA limit as the Tesla charger has a high transient DC leak that may be enough to trip things at the start of the charge. An electrician should have tested the existing DC leakage through any RCD so would know how close to the limit you might be. fwiw - we had ~22mA leakage through ours and the Tesla UMC was enough to trip the RCD. We had to have the circuit moved to a different RCD. DC leakage is often normal (especially with electronic gear) and it might be a few mA per device, but it all adds up.

 

[Adopado]

Fully competent person and registered against building control if you are in England as it is outdoors work so subject to part P.

The electrician should technically been told that it is for outside car charging so they would need to stuck to stricter regs but that is a tough one to prove if anyone came asking about it - more of a thing that may happen after an issue. This is more important if fitting a commando socket though.

As for closing cover, to add to the above, you may well have problems as it is a switched plug which will likely cause the sockets to be off centre. If that is the case and the centres to not line up exactly with the weatherproof openings, the thick cable on the UMC may make it very hard/impossible to kink the cable to line up correctly. An easy one to check if its likely to be an issue prior to needing it.

Another gotcha is how the socket is protected, particularly if it shares an RCD with other circuits in the house. Its not unheard of tripping a shared RCD due to exceeding the 30mA limit as the Tesla charger has a high transient DC leak that may be enough to trip things at the start of the charge. An electrician should have tested the existing DC leakage through any RCD so would know how close to the limit you might be. fwiw - we had ~22mA leakage through ours and the Tesla UMC was enough to trip the RCD. We had to have the circuit moved to a different RCD. DC leakage is often normal (especially with electronic gear) and it might be a few mA per device, but it all adds up.

If this was fitted as a general purpose outside socket then I don’t see that it would have been required to meet EV charging spec. It will be as good as any other household 13amp socket. Hardly anyone who is using temporary 13amp socket charging has it up to EV spec. Of course if this WAS fitted as a dedicated ev charge point then all the requirements as per your post would require to be met.

 

[Mr H]

Just plug it in, if there is a bang and flash then get someone to look at it, otherwise just sleep with one eye open

 

[MrBadger]

If this was fitted as a general purpose outside socket then I don’t see that it would have been required to meet EV charging spec. It will be as good as any other household 13amp socket.

I cant find the official source, but this one summarises it, albeit an electricians take on the matter, but it is inline with my recollection of the regs.

Typical 13A sockets, as described in Mode 1 charging earlier, are very useful in the home or the office. But if used to charge an EV for around ten or more hours, they can become damaged. They’re simply not designed to work at full capacity for these prolonged periods. Therefore, any compliant BS 1363 socket intended for EV charging should be clearly marked as such, to show that they are made for this purpose, and are generally more capable of taking the high electrical loads associated with EV charging.

Source - The 18th Edition and EV Charging

As you say, its likely to be no different to other 13A sockets, but regs is regs if the electrician knows the intended purpose. I also have a nagging feeling that irrespective of the purpose of the socket, different earthing arrangements apply to new outside sockets.

 

[mikeyg_ev]

Charged for 12 h overnight at my mum’s place (literally granny charging). When I finished one of the pins on the plug was blackened and there were scorch marks around the socket. Sure it was a defective socket (now replaced) but I’ll be a lot more careful and check it a couple of times over the first hour of charging in future.
Lucky I used an extension lead and didn’t damage the plug on the charger itself.

 

[Adopado]

Charged for 12 h overnight at my mum’s place (literally granny charging). When I finished one of the pins on the plug was blackened and there were scorch marks around the socket. Sure it was a defective socket (now replaced) but I’ll be a lot more careful and check it a couple of times over the first hour of charging in future.
Lucky I used an extension lead and didn’t damage the plug on the charger itself.

How was the plug with the blackened pins? It is more common for the heat to come from the plug due to the fuse/connections or loose screw connections. Sometimes it’s therefore the plug that cooks the socket! (It can be either of course. ) It’s certainly a good idea to check temperatures when charging for the first time on an unkown socket.

 

[realityagain]

I'm planning to charge mine from a 3-pin in my garage, due to some complications at the moment with getting a wall charger installed (long story).
I've heard some people recommending to limit this to 8amps from the Tesla's side?
Anyone here have experience/tips long term relying on a 3-pin? I have some fast chargers local, that I will use before longer journeys - but usually day-today my milage isn't very high.

 

[Adopado]

I'm planning to charge mine from a 3-pin in my garage, due to some complications at the moment with getting a wall charger installed (long story).
I've heard some people recommending to limit this to 8amps from the Tesla's side?
Anyone here have experience/tips long term relying on a 3-pin? I have some fast chargers local, that I will use before longer journeys - but usually day-today my milage isn't very high.

I suggest that the first time you run the charge at its full speed (10amps) using the Tesla UMC (Universal Mobile Connector as supplied with the car). Touch the plug and socket area to check how warm they are getting after half an hour then after a couple of hours. You would expect to feel warmth but not hot to the touch. Unless the electrics are below par there shouldn't be an issue charging at 10amps. Some people have been doing this for years (even though use of the UMC is not really intended as the primary method of charging). Another recommendation is to avoid using an extension but in practice many of us have done this. The extension should be "heavy duty" and MUST be fully unwound. Heavy duty in my book means cable cores of at least 1.5mm.

 

[bhanorthy]

I'm planning to charge mine from a 3-pin in my garage, due to some complications at the moment with getting a wall charger installed (long story).
I've heard some people recommending to limit this to 8amps from the Tesla's side?
Anyone here have experience/tips long term relying on a 3-pin? I have some fast chargers local, that I will use before longer journeys - but usually day-today my milage isn't very high.

I live in a rented house so there is no way I am paying for a chargepoint for somewhere I dont own.
I use the 3pin exclusively in the garage. First time around stick it at 10amps and check it every few hours for heat. It should be warm but not red hot to touch.

Once you are confident the wiring is sound then fill your boots. I've been doing it for over a year, consistently with no issues.

 

[Adopado]

I live in a rented house so there is no way I am paying for a chargepoint for somewhere I dont own.
I use the 3pin exclusively in the garage. First time around stick it at 10amps and check it every few hours for heat. It should be warm but not red hot to touch.

Once you are confident the wiring is sound then fill your boots. I've been doing it for over a year, consistently with no issues.

The UMC only runs at 10amps when used with its 3 pin plug ... you can't inadvertently charge at a higher rate!

 

[M3noob]

I've been running at 10 amps with my UMC since March last year. No probs. My garage is on a 20 amp breaker. On Octopus Go so runs 4 hours at night.

 

[mikeyg_ev]

How was the plug with the blackened pins? It is more common for the heat to come from the plug due to the fuse/connections or loose screw connections. Sometimes it’s therefore the plug that cooks the socket! (It can be either of course. ) It’s certainly a good idea to check temperatures when charging for the first time on an unkown socket.

Plug fine inside. Could see The pin blackened and pitted. Guessing the contacts in the socket weren’t very good and only made limited contact with the pin. Could have been like it for 30 years but only ever had a lamp plugged in.

 

[tsh2]

I would wonder if that socket would be likely to risk the plug getting warm. Probably not, but it might.

 

[Adopado]

I would wonder if that socket would be likely to risk the plug getting warm. Probably not, but it might.

With that kind of blackening and pitting you would be likely to smell it too.

 

[imstitch]

I did a couple of full 24hr charges in an older plug recently and the plug was all cracked and damaged afterwards. Swapped the plug out for a new one and now charge on 6A instead of 10A, no problems since. It's slower but better than a house fire.

 

[Adopado]

I did a couple of full 24hr charges in an older plug recently and the plug was all cracked and damaged afterwards. Swapped the plug out for a new one and now charge on 6A instead of 10A, no problems since. It's slower but better than a house fire.

Do you mean socket? The plug on the UMC would surely be perfect. If the socket has been replaced with a standard spec item and properly wired and fitted you should not be risking a house fire by charging at the standard 10amps. I’m concerned that people reading this thread are going to get the impression that home charging is routinely dangerous!

 

[Adopado]

Do you mean socket? The plug on the UMC would surely be perfect. If the socket has been replaced with a standard spec item and properly wired and fitted you should not be risking a house fire by charging at the standard 10amps. I’m concerned that people reading this thread are going to get the impression that home charging is routinely dangerous!

Of course if you charge with a known to be old or questionable plug or socket then you take what you get!